ZIOL2201 datasheet(81/92 Pages) RENESAS

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ZIOL2xxx Datasheet

April 26, 2016

Appendix A

ZIOL2xxx Diagnostic Techniques

A.1. General Remarks

Since chapter 3.3 described the basic principles in terms of IC control circuit, this chapter deals with details of

techniques for analyzing the internal IC state in order to prevent IC damage or unwanted system operation. The

following description references to Figure 3.8 (The Basic Scheme of the IC Self Protection) of the ZIOL2xxx

datasheet.

A.2. Overload Counter Behavior and Peak Register Access

The ZIOL2xxx contains five peak registers (status registers) which are associated with overload counters as

follows:

• Over-current counter assigned to the LS driver of the COM channel – register[21]

• Over-current counter assigned to the HS driver of the COM channel – register[22]

• Over-current counter assigned to the LS driver of the AUX channel – register[23]

• Over-current counter assigned to the HS driver of the AUX channel – register[24]

• Over-temperature counter– register[25]

Only in case an overload is present, thus the overload counter is in the count up mode, the value of the overload

counter will be copied into the peak register if the overload counter value is greater than the peak register value.

This conditional copy operation is performed within each cycle of IC control circuit as illustrated in Figure 10.1.

Figure 10.1 shows two different scenarios of the behavior of a peak register. Scenario A shows the development

of the peak register value if no read access happened. In contrast to that scenario B shows several read accesses

within the same sequence of consecutive overload periods. Since the peak register is cleared after each read

access, it resumes within the next cycle of the IC control circuit to the present overload counter value only if

overload is present.

A lock will be generated if the overload counter reaches a configured maximum value which is representing

according to the following formula the related “Assert time” of the lock circuit (refer to Figure 3.15, Figure 3.16,

Figure 3.17).

Val

AssertTime

clk

AssertTime

∗

Where Tclk is the for the lock circuit configured counter clock (refer to Figure 3.15, Figure 3.16, Figure 3.17) having

a period of 200ns, 1ms, 8ms, or 16ms and where AssertTimeVal is the in the related assert time register stored

value.

Similarly to that, thus using a similar formula the lock time of the related lock circuit (refer to Figure 3.15, Figure

3.16, Figure 3.17) can be calculated.

LockTimeVa

clk

LockTime

∗

Where Tclk is the for the lock circuit configured counter clock (which is the same clock as used for the overload

counter, refer to Figure 3.15, Figure 3.16, Figure 3.17) having a period of 200ns, 1ms, 8ms, or 16ms and where

LockTimeVal is the in the related assert time register stored value.

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